This study involving both interinstitutional and interdisciplinary collaboration, investigates the incidence and prevalence of depression and its correlates in 1000 children in a group of the general population, have been subjects since birth in 1972, of an ongoing longitudinal study in Dunedin, New Zealand. The frequency of core symptoms and associated symptoms of depressed and non-depressed children will be determined. The prevalence of depression among the parents also will be investigated. Depression in children and parents will be identified by a psychiatrist using DSM III Criteria for Major Depressive Disorder. After screening procedures, the depressed children will be evaluated further by the SADS-E and Children's Psychiatric Rating Scale and their parents will fill out the Achenbach Child Behavior Checklist for the children. The SADS-E will be administered to the parents of depressed children. The depressed children will be matched with a control group of non-depressed children in regard to age, sex, socioeconomic status, and intelligence quotient. The depressed children will be reevaluated annually. All of the children in the Dunedin Study will be reevaluated at the regular two year follow up to look for new cases of depression and any changes in previous symptomatology.